129. Liquid Crystalline Phase Behavior and Sol–Gel Transition in Aqueous Halloysite Nanotube Dispersions
作者：ZQ Luo, HZ Song, XR Feng, MT Run, HH Cui, LC Wu, JG Gao, and ZG Wang
關鍵字：Halloysite Nanotube, liquid crystalline gel, dispersions
論文來源：期刊
具體來源：Langmuir, 2013, 29,12358–12366
發表時間：2013年
Abstract: The liquid crystalline phase behavior and sol–gel transition in
halloysite nanotubes (HNTs) aqueous dispersions have been investigated
by applying polarized optical microscopy (POM), macroscopic observation,
rheometer, small-angle X-ray scattering, scanning electron microscopy,
and transmission electron microscopy. The liquid crystalline phase
starts to form at the HNT concentration of 1 wt %, and a full liquid
crystalline phase forms at the HNT concentration of 25 wt % as observed
by POM and macroscopic observation. Rheological measurements indicate a
typical shear flow behavior for the HNT aqueous dispersions with
concentrations above 20 wt % and further confirm that the sol–gel
transition occurs at the HNT concentration of 37 wt %. Furthermore, the
HNT aqueous dispersions exhibit pH-induced gelation with more intense
birefringence when hydrochloric acid (HCl) is added. The above findings
shed light on the phase behaviors of diversely topological HNTs and lay
the foundation for fabrication of the long-range ordered nano-objects.